mike, i cant sleep on my back on my $1200 home mattress but found it easy in my hammocks. fwiw, it supports my body on a weird 2/3rds position, whereas im on my side and back.
and i can sleep in the 'mock on my side, legs stretched straight or pulled up slightly to fetal style.. i prefer on my stomach at home, due to deviated septum but the hammock figures it out for me.. i dont ask why, it just works.

let me know what model youre interested in. or come on one of our group hikes and try a hammock for yourself.
there just aint nothing better than stargazing from your hammock, listening to Plastic Surgery Disasters on the ol' iPod

belly sleeping in a hammock? I don't recommend it. I had an "incident" a few months ago while sleeping in my hammock -- during the middle of the night, I woke up and decided to roll over because the full moon was really bright -- and proceeded to roll straight on over into thin air, landing on the ground with a loud surprised THUMP. my butt was bruised for 2 weeks and my friends still tease me about it, since I had given them the classic "tents are for sissies" speech around the campfire that night ;)

the hammock of today is the Warbonnet Blackbird made in different weights depending on your weight.. i use a single layer 1.1 ripstop nylon.* full bug netting, full zipper, full structural ridgeline. I converted the (very good) webbing/ring suspension to an even better Whoopie Sling suspension and the total weight is now 19 ounces. this pic is me sleeping on my back ( ) at Kendrick Peak.

do you see that big lump at the foot area of the hammock? that's the built in "footbox" that will let you lay flatter. the hammock also has a shelf inside so you dont have to reach out for water, books, headlamp, shoes, whatever. its about 2 square feet.

the netting is flipped over the top of the hammock and under me is the product i make, a 2" loft goose down underquilt. tarp is a MacCat standard in spinnaker. guy inside is awesome.

lets see, if i recall the weights are as follows.
warbonnet 1.1: 19oz
te-wa underquilt: 13oz
maccat standard: 11.8oz
te-wa topquilt: 12.4oz
pad for lower legs: 3oz
thats roughly 3.7 pounds
that rivals even the most ultralight coffins.. and you can situp, cook dinner, pitch and tear down under the protection of your tarp. this winter im rigged up to go down to the single digits in a hammock all for the weight of one two-man freestanding tent.
my old setup, even tho ultralight, was a BA insul. air core pad, a tarptent contrail, a western mountaineering ultralite, and a small pillow.
but getting a really good night's sleep is hands down the best thing ever. there is no need to wake up sore from sleeping on a little crappy pad like some of these ultralighters do. the days of tossing are over.